This invention relates to certain novel ethers and to processes for the preparation of the same. In particular, this invention relates to an improved method for the continuous separation and recovery of products from reactants during the course of the reaction in the synthesis of ethers from branched olefins and alcohols in the presence of an acid catalyst.
The reaction of olefins with alcohols using acid catalysts such as p-toluene sulfonic acid to form ethers is known as shown, for example, in the aforementioned application, Ser. No. 658,435.
This earlier method, as in similar prior art methods, involves a homogeneous, single liquid-phase reaction in which, because of considerations of thermodynamic equilibrium, it is often necessary that large excesses of alcohol be present to maximize the yield. This, in turn, leads to a serious disadvantage in that these large amounts of alcohol must then be handled during recycling, together with unreacted olefin and catalyst, after separation of the ether product. This separation is generally accomplished by neutralizing the acid and water washing the alcohol from the organic phase before distilling the unreacted olefin from the product. The neutralization step, in turn, is undesirable because the acid catalyst is converted thereby to a less valuable salt, and distillation of the unreacted alcohol from the reaction medium is necessary for recycle.
Taken as a whole, then, this conventional, homogeneous, single-phase system is characterized by complicated and economically disadvantageous separation and recovery systems together with the handling of large volumes of excess alcohol.
In related art, W. Treibs, Berichte (1937), Vol. 70, pages 589-594, describes a process of preparing ethers from olefins and alcohols. Significantly, however, analysis of Treibs examples reveal that unlike applicant's process, as hereinafter described, said ethers are formed only when no water is present in the system. On the other hand, when Treibs example do describe hydrous systems, only alcohols corresponding to the olefin starting materials are recovered. By contrast, applicant's process does not yield alcohols.